A semiconductor device structure comprises stacked tiers each comprising at least one conductive structure and at least one insulating structure longitudinally adjacent the at least one conductive structure, at least one staircase structure having steps comprising lateral ends of the stacked tiers, and at least one opening extending through the stacked tiers and continuously across an entire length of the at least one staircase structure. The at least one conductive structure of each of the stacked tiers extends continuously from at least one of the steps of the at least one staircase structure and around the at least one opening to form at least one continuous conductive path extending completely across each of the stacked tiers. Additional semiconductor device structures, methods of forming semiconductor device structures, and electronic systems are also described.